II. Nutrition

Abstract

PHYSIOLOGY OF DIGESTIONASSMANN(I) has recently studied the weights of the stomach, intestine and the alimentary contents of bullocks. He found that the empty stomach accounts for 3-5% of the body weight, the empty intestine 1-7-2-4%, the stomach contents 8-6-16-6% and the intestinal contents 1-7-5%. For comparison with non-ruminants it may be noted that in pigs the corresponding figures were 0-5-0-7, 2-5-3-2, 0-25-0-45 and 1-26-1-86%. In large bullocks the alimentary tract and contents accounted for 30 % of the body weight. Swett et al.(2) in a very comprehensive study of the weights of the various organs found similar results.The effect of feeding long and short hay on chewing and rumination has been investigated by Kick & Gerlaugh(3). Using three steers, 18-32 months old, with fistulae, alfalfa hay was fed uncut, 2 in. long, J in. long and ground. After 24 hr. the rumen contents were removed, weighed and sampled. With the more finely ground fodder the number of chews decreased, although the younger animals needed mare chews than the older. There was little difference between the uncut hay and the 2 in. sample. The shorter material gave less rumination. After 24 hr. the amount of fibre in the rumen decreased from the uncut to the \ in. sample but increased with the ground hay. With the two younger steers the protein in the rumen tended to diminish with the fineness of the hay. In a later paper Kick et al. (4) found that there was a saving in energy on grinding hay. Much more chewing energy was expended during rumination of hay alone than during that of a mixed ration. When the ration consisted of a protein supplement and maize only, the amount of rumination was reduced to a minimum with no ill effects to the animals during the 2-week period. Columbus (5) investigated the effect of different foods on the rate of passage of the food, using the dyed straw method. The rate was influenced by the physical properties of the food, fine division giving quick passage. Green fodder was more rapidly digested, but the rate of digestion was diminished with an insufficient amount of roughage. Exercise also accelerated the rate of digestion.Analysis of the saliva of cattle, sheep, goats and pigs has shown that the amylase content is very low (6).By a mask spirometer method, Washburn & Brody(7 8) measured simultaneously the rumen and expired gases from a cow. The ratio between the fermentation carbon dioxide and the combustible gases was subject to considerable but characteristic variations. The total energy losses in fermentation gases were 12-16% of the feed energy intake or 25-40% of the maintenance requirement. Rumen oxygen and nitrogen values showed an aerobic fermentation. As digestion proceeded the values for the rumen gases approached those of the intestinal gases.Regarding bacterial digestion of cellulose in the fore-stomachs of ruminants Woodman & Evans (9) have made further observations from their in vitro studies. From previous experiments(io,ii,i2) these authors had concluded that although the normal end products o...

Changes in composition of spider orb web sticky droplets with starvation and web removal, and synthesis of sticky droplet compounds

“…Insects, likewise, are either unable to synthesize Cho or synthesize insufficient Cho (via methylation of phosphatidylethanolamine), making it a nutritional essential (Dadd, 1985). Limited synthesis of Cho from phosphatidylethanolamine also occurs in at least some crustaceans (Bilinski, 1962;Shieh, 1969;Brichon et al, 1980;D'Abramo and Baum, 1981) (Morris, 1991).…”

677. The effect of variations in nutrient intake upon the yield and composition of milk: I. Variations in the amount and type of concentrates fed in winter rations

“…P.E./IO lb. milk in view of the well-recognized absence of response to additional amounts of protein (7,12,13,14).…”